1. Field of the Invention
This invention relates to emergency illumination systems, particularly those having indicators that effectively communicate an exit route. It also relates to illuminating fibers displaying one or more illumination colors.
2. Information Disclosure Statement
In many situations and environments, it is necessary to provide emergency systems that direct persons to exits or other areas of safety. Areas such as airplanes, industrial environments and theatres all require systems to direct persons in the event of a power outage, fire, or other emergency. Such systems must have certain characteristics to be effective. They must be highly visible, both in darkness and in situations where smoke or other environmental conditions reduce visibility. They must also be reliable and able to produce illumination regardless of the state of the main power supply. Finally, they must be able to communicate escape routes effectively and unambiguously to users. Many systems have been utilized and promoted in the prior art.
The following patents involve the use of lamps or incandescent bulbs as illumination sources in pulsed lighting systems. U.S. Pat. No. 4,347,499 describes an emergency guidance system having a plurality of discernable means, which are electronically interconnected to provide a sequentially pulsed system. The system provides a moving light pattern to direct occupants to a safe exit in an airplane or public building. The lighting source is a low voltage lamp or high intensity bulb.
U.S. Pat. No. 4,029,994 describes an emergency lighting system for indicating the direction of emergency exits of an airplane or other passenger carrier. The flashing light system incorporates battery powered electronic flash lamps along the aisle of a carrier and a means to provide a stroboscopic sequential firing of the lamps to create the illusion of a moving light beam. The preferred light source is a gas discharge type of tube or lamp.
U.S. Pat. No. 4,794,373 describes a lighting strip apparatus for visually guiding the occupants out of a structure. The apparatus is comprised of a carpet overlying the floor and a flexible lighting strip positioned underneath the carpet. A small incandescent bulb is the described light emitting means. The light-emitting means may be sequentially activated to impart a visual direction signal to a viewer.
The above systems utilize lamps or incandescent bulbs as an illumination means. These have limitations in hazardous areas and have all the complications associated with replacement and cleaning of a lamp type system.
Other patents concern the use of phosphorescent/luminescent materials as an emergency directional means. U.S. Pat. No. 4,401,050 describes a phosphorescent and tactile escape route indicator that can be followed by a person in complete darkness or where visibility is impaired. In a preferred embodiment the indicator is a tape having formed there-on protruding direction indicia, such as an arrow or arrowhead. The indicia contain a phosphorescent material capable of emitting a glow immediately after loss of conventional lighting.
U.S. Pat. No. 5,961,072 describes an emergency lighting system comprised of photoluminescent strips mounted on the floor of a vehicle, such as an aircraft. A channel extrusion is secured to the floor and a two-layer photoluminescent strip is held between the channel and a transparent cover. The double layer increases light output. In a preferred embodiment a photoluminescent dye or ink of a different color from the photoluminescent strip is used to mark words or pictograms onto the strip.
U.S. Pat. No. 6,237,266 describes an evacuation route indicator that includes a carpeted strip having direction-indicating indicia formed thereon. The indicia are a photoluminescent material and are formed either recessed or raised in relation to the carpet surface. Indicia may include a series of geometric shapes of increasing or decreasing size or other symbols which represent direction.
Although no electricity is required to operate the previously described set of inventions, phosphorescent materials have a limited functional period. They also continue to point to exit routes that may in fact be blocked, by fire or other hazards. The static indicator cannot change color, and they cannot provide a motion or strobe effect.
U.S. Pat. No. 6,183,102 describes a transparent tubular member containing a volume of long persistence phosphorescent material. The tubular member is flexible and preferably only coated on the inside with the phosphorescent material. In a preferred embodiment a plurality of light emitting diodes at spaced intervals in the interior of the tubular member intermittently flash to recharge the luminescent capability of the phosphorescent base material. This system overcomes the problem of a limited functional period, but still continues to point to exit routes that could be blocked; it cannot change color, and cannot provide a motion or strobe effect. It also has the problems associated with using light bulbs.
U.S. Reissue Pat. No. 36,642 describes a fiber-optic lighting system designed to transmit light from a remote light source to individual light fixtures. Elongated fiber optic light guides extend out to light fixtures throughout an airplane cabin. The fixtures are comprised of reflectors, lenses and globes and do not contain lamps. The light guides are used for valance light fixtures, reading lights, and floor strips for directional emergency lighting. The means to distribute light out of the fiber are not integral to the fiber and the fixtures are susceptible to damage. The preferred light source is a high intensity discharge lamp, such as a xenon metal halide lamp. These give off relatively high amounts of heat and may not be suitable in a potentially combustible or explosive environment.
U.S. Pat. No. 4,521,839 describes a strip lighting system comprising a string of electrically connected light bulbs contained within a flexible waterproof tube. The bulbs are removable so that they can be individually replaced if necessary. U.S. Pat. No. 4,376,966 describes a strip light comprised of a series of electric lamps spaced along the interior of a flexible vinyl tube. The tube is disposed within a channel-like mounting bracket having a restricted entrance through which the tube can be viewed. Although the flexible tubing systems described can resist a wet environment, they still use an electrical lead to power the bulbs, which could be hazardous if exposed to potentially explosive environments. They also have the problems associated with replacing bulbs that burn out and they cannot produce a chasing effect.
The following patents disclose chasing light systems. U.S. Pat. No. 5,321,593 describes a strip lighting system using light emitting diodes. The system can produce a static lighting effect or a chasing light effect. The system applies reverse voltage to the LED's to achieve a four-channel chase with only three conductors. U.S. Pat. No. 4,263,640 describes a lighting device for producing a chasing light effect. The invention comprises one or more flexible transparent tubes which house a star connected network of miniature light sources. The light sources are disposed in a string array. A sequencer drives the star connected network of miniature light sources. The two chasing light systems described above use electrical bulbs that are inappropriate in challenging environments. The systems also have all the problems associated with changing and maintaining a bulb based illumination system.
U.S. Pat. No. 4,389,085 describes a lighting system utilizing sunlight. In a preferred application, sunlight or an artificial light source such as a laser beam, is passed through an optical transmission line. In a preferred application, one or more optical fibers having light diffusion sites along the length illuminate an emergency exit or staircase. The diffusion sites may be a recess in the cladding, a hole in the cladding filled with an optically transparent medium or a transparent optical element. In another application, special artificial light sources such as laser generators capable of emitting various colored beams are provided so that the light may be flashed or changed in color to communicate information. The described system uses a fiber with a single cladding and illumination is by passive lighting (sunlight). The light source is not integral to the fiber and there is no means to indicate path direction. There is further no means to easily change the emitted wavelength; the use of a prism in selecting wavelengths makes it difficult to switch wavelengths and adds complexity to the system. Also, there are no means to produce a chasing effect. Furthermore, the effective lengths of fiber that can be used is restricted. This system is also disadvantageous in places that do not receive a sufficient amount of sunlight, in environments such as airplanes that have insufficient surface area to accommodate large arrays of sunlight collectors, or where conditions may be present that could damage exposed sunlight collectors.
There remains a need for an illuminating emergency device that has direction indicating elements and is capable of emitting light of different colors to communicate exit status. It would also be useful to have an illuminating emergency device that is side pumped for greater energy input, double cladded to utilized fiber laser elements, and possessing light emitters that are integral to the fiber to enhance reliability.